An airfoil is a cross section of airplanes wings. Wings of airplanes produce lift by creating pressure difference between upper and lower surface of wings. This so called lift enables the airplanes to fly helps them remain high in the sky. One of the major problems that an airplane experienced is flow separation .Which causes the reduction of lift and increment of drag. Drag is the resisting force of air. A lot of researchers working hard since few decades to minimize this flow separation effect. As a result of their hard working concept of vortex generator have been developed .Which delays the boundary layer separation. Though there are various types of vortex generators. In the present review a special type of vortex generator namely dimple is focused. Since last half of decades investigations related to dimples grew the attention of many researchers .A lot of numerical and experimental investigations have been conducted by several researchers around the world related to dimples effect on airplanes wings cross section or airfoils. The outcomes of those investigations are extremely tremendous. Those outcomes indicate that dimples of different size and shape can play a vital role in designing of airplanes wings. This present study or review try to sum up all of those researches in a nut shell.
International Journal of Research Available at https://edupediapublications.org/journals e-ISSN: 2348-6848 p-ISSN: 2348-795X Volume 04 Issue 05 April 2017 Fig.4.8 Constructed model with circular dimples. Fig 5.2 Experimentation of dimpled airfoils using wind tunnel. 6. Conclusions Fig.4.9 Constructed Model with combination of hexagonal and circular dimples. 5. Experimental Investigations Experimentations were performed in Aerodynamics Laboratory of Department of Mechanical Engineering at Khulna University of Engineering and Technology with subsonic wind tunnel of 1 m× 1 m rectangular test area using different types of dimpled models by Rubiat Mustak himself. Fig 5.1 Experimentation of dimpled airfoils. From the above study it is seen that dimples which reduce the drag of golf balls can reduce the drag of airfoils. Several researchers around the world have shown both in numerical and experimental ways that dimples plays an important role in drag reduction. They also assist to have more lift hence more lift to drag ratio. Dimpled airfoils make the aircrafts more maneuverable. They increase aerodynamic efficiencies. Aerodynamic efficiency is one of the key parameters that decides the weight and cost of an aircraft. Enhanced aerodynamic efficiency is critical to both business and military aircrafts. For business airplane, enhanced optimal design decreases working expenses. So future research related to dimpled airfoil have a probability of great impact in aircraft manufacturing. 7. References  Dr. P. N. Modi, Dr. S. M Seth, Hydraulics and Fluid Mechanics Including Machines (In SI Unit), new edition 2005-2006, Standard Book House.  John D. Anderson, J.R, Introduction to Flight Dynamics, Third Edition, Mc Graw-Hill International Editions, Aerospace Science Series.  E. L. Houghton, P. W. Carpenter, Aerodynamics for Engineering Students, Fourth Edition, Edward Arnold Publisher.  Charles E. Dole, Flight Theory and Aerodynamics, A Wiley Inter science Publication.  Davies, J.M., The aerodynamics of golf balls, J of Applied Physics, 1949, Volume 20, Issue 9, Pages 821-828.  Deepenshu Srivastav, Flow Control Over Airfoils Using Different Shaped Dimples, International Conference on Fluid Dynamics and Thermodynamics Technologies (FDTT) IPCSIT, Volume 33, IACSIT Press, Singapore, 2012. Available online: http://edupediapublications.org/journals/index.php/IJR/ P a g e | 845
International Journal of Research Available at https://edupediapublications.org/journals e-ISSN: 2348-6848 p-ISSN: 2348-795X Volume 04 Issue 05 April 2017  M. Moses Devaprasanna, N. Maheswaran, M. Harish, Prof. A. Sankaran, CFD study on aerodynamic effects of dimples on aircraft wings, International Journal of Engineering & Science Research,Volume-6,Issue-11,Pages pp.245-248,2016.  P. Booma Devi, Dilip A. Shah ,Computational Analysis of Cavity Effect over Aircraft Wing, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering,Volume-10,Issue-4,2016.  Livya. E, Anitha. G, Valli. P, Aerodynamic analysis of dimple effect over aircraft wing, International journal of mechanical aerospace industrial and mechatronics engineering, Volume 9. Number 2, 2015, Pages 350-353.  Thamodharan B, Shaik Mohamed Nagutha G,Sacraties A , Devaki P ,Numerical Analysis of Effect of Dimples on Aero-dynamics of an Airfoil, International Conference on Explorations and Innovations in Engineering & Technology (ICEIET - 2016). Available online: http://edupediapublications.org/journals/index.php/IJR/ P a g e | 846